Introduction. Suero costeno is an autochthonous product from the Colombian Caribbean region, and it is obtained by naturally fermenting raw milk, so it keeps all of its nutritional ingredients. Objective. Determine and compare the physical/chemical and microbiological characteristics of the milk and of the suero costeno from Arjona, Turbaco and Carmen de Bolivar. Materials and methods. The physical/ chemical and microbiological characteristics of the milk and of the suero costeno were determined and compared according to what is established by the Colombian regulations. Results. The cryoscopic index of the milks produced in Turbaco, Arjona and Carmen de Bolivar does not meet the regulations, while the microbiological tests are within the ranks allowed. The sueros costenos from Carmen de Bolivar, Arjona and Turbaco contain Escherichia coli, fecal Coliforms and Staphylococcus aureus coagulase above the levels allowed. The suero costeno produced industrially meets the microbiological and physical/chemical quality standards demanded by the regulations. Conclusion. The high microbial load contained in not industrially produced sueros costenos is a consequence of the deficient hygienic and sanitary conditions under which they are produced in the aforementioned towns.